Search results for "Bandwidth"
showing 10 items of 250 documents
HF Noise Measurements Based on Software Defined Radio Dual Receiver and Two Orthogonal Inverted Vee Antennas
2020
Increasing the data transfer rate in the High Frequency (HF) range involves enlarging the bandwidth of the channel from the standard value of 3 kHz to values of 6, 12, 24, 48 and even 96 kHz. Real-time evaluation of the noise power in the channel under such conditions is essential. This paper aims to implement an automated system for real-time measurement of noise in the HF range. It is composed of two Software Defined Radio (SDR) synchronized receivers and two orthogonal Inverted Vee antennas. Testing the system demonstrates its ability to distinguish between noise and signals generated as a result of human activity. Preliminary results of measurements performed in an urban location are co…
Design of large scale sensors in 180 nm CMOS process modified for radiation tolerance
2019
International audience; The last couple of years have seen the development of Depleted Monolithic Active Pixel Sensors (DMAPS) fabricated with a process modification to increase the radiation tolerance. Two large scale prototypes, Monopix with a column drain synchronous readout, and MALTA with a novel asynchronous architecture, have been fully tested and characterized both in the laboratory and in test beams. This showed that certain aspects have to be improved such as charge collection after irradiation and the output data rate. Some improvements resulting from extensive TCAD simulations were verified on a small test chip, Mini-MALTA. A detailed cluster analysis, using data from laboratory…
Towards CEP stable sub two cycle IR pulse compression with bulk material
2010
We demonstrate both experimentally and numerically that self-steepening during propagation in a hollow-fiber followed by linear propagation through glass in the anomalous dispersion enables pulse compression down to 1.9 cycles at 1.8 micron wavelength.
Amplifier similariton fibre laser with nonlinear spectral compression
2012
We propose and numerically demonstrate a new concept of fibre laser architecture supporting self-similar pulse evolution in the amplifier and nonlinear pulse spectral compression in the passive fibre. The latter process is beneficial for improving the power efficiency as it prevents strong spectral filtering from being highly dissipative.
Fiber-based measurement of temporal intensity and phase profiles of an optical telecommunication pulse through self-phase modulation
2018
International audience; We propose and experimentally validate an all-fiber based approach to characterize the phase and intensity profiles of optical pulses. Based on three optical spectra affected by different levels of self-phase modulation, we were able to reconstruct the temporal details of pulses typical of optical telecommunications.
Highly efficient few-mode spatial beam self-cleaning at 15µm
2020
We experimentally demonstrate that spatial beam self-cleaning can be highly efficient when obtained with a few-mode excitation in graded-index multimode optical fibers. By using 160 ps long, highly chirped (6 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a one-decade reduction of the power threshold for spatial beam self-cleaning, with respect to previous experiments using pulses with laser wavelengths at 1030-1064 nm. Self-cleaned beams remain spatio-temporally stable for more than a decade of their peak power variation. The impact of input pulse temporal duration is also studied.
Parabolic pulse generation with dispersion decreasing optical fiber
2007
We experimentally demonstrate the possibility to generate parabolic pulses via a single dispersion decreasing optical fiber with normal dispersion. We numerically and experimentally outline the influence of the dispersion profile.
Phase-locked soliton pairs in a stretched-pulse fiber laser.
2002
We report the experimental observation of stable pulse pairs with a ±π/2 phase difference in a passively mode-locked stretched-pulse fiber ring laser. In our setup the stabilization of interacting subpicosecond pulses is obtained with a large range of pulse separations, namely, from 2.7 to 10 ps, without the need for external control. © 2002 Optical Society of America
Coupling between counterpropagating cladding modes in fiber Bragg gratings
2011
We present an experimental demonstration of energy transfer between counterpropagating cladding modes in a fiber Bragg grating (FBG). A strong FBG written in a standard photosensitive optical fiber is illuminated with a single cladding mode, and the power transferred between the forward propagating cladding mode and different backward propagating cladding modes is measured by using two auxiliary long period gratings. Resonances between cladding modes having 30 pm bandwidth and 8 dB rejection have been observed.
Temporal and Spectral Nonlinear Pulse Shaping Methods in Optical Fibers
2015
The combination of the third-order optical nonlinearity with chromatic dispersion in optical fibers offers an extremely rich variety of possibilities for tailoring the temporal and spectral content of a light signal, depending on the regime of dispersion that is used. Here, we review recent progress on the use of third-order nonlinear processes in optical fibers for pulse shaping in the temporal and spectral domains. Various examples of practical significance will be discussed, spanning fields from the generation of specialized temporal waveforms to the generation of ultrashort pulses, and to stable continuum generation.